Develop Reference

Cannot resolve method 'flatMap(<lambdaexpression>)' error

I am new to apache spark and trying to run the wordcount example . But intellij editor gives me the error at line 47 Cannot resolve method 'flatMap()' error.
Edit :
This is the line where I am getting the error
JavaRDD<String> words = lines.flatMap(s -> Arrays.asList(SPACE.split(s)).iterator());

It looks like you're using an older version of Spark that expects Iterable rather than Iterator from the flatMap() function. Try this:
JavaRDD<String> words = lines.flatMap(s -> Arrays.asList(SPACE.split(s)));
See also Spark 2.0.0 Arrays.asList not working - incompatible types

Stream#flatMap is used for combining multiple streams into one, so the supplier method you provided must return a Stream result.
you can try like this:
lines.stream().flatMap(line -> Stream.of(SPACE.split(line)))
.map(word -> // map to JavaRDD)

flatMap method take a FlatMapFunctionas parameter which is not annotated with #FunctionalInterface. So indeed you can not use it as a lambda.
Just build a real FlatMapFunctionobject as parameter and you will be sure of it.

flatMap() is Java 8 Stream API. I think you should check the IDEA compile java version.
compile java version

javac incompatible types error in eclipse

While compiling the code I get an unexpected error, which never occurred before, it says that I cannot convert from int to an Object...
Code:
maxBundles = max;
bundleProgressBar.setMaximum(max);
bundleProgressLabel.setText("Updating Components...");
// Tell JS that the state is Installing.
Object[] arr = { 1 };
error:
`103: error: incompatible types
[javac] Object[] arr = { 1 };`
I know this is a problem with eclipse, because it worked before, so my question is what can I change to resolve it...

What you're trying to do is called autoboxing - the process of converting a primitive (int in this case) to its Object represantation (Integer in this case), automatically. More on autoboxing and unboxing here.
Autoboxing was introduced in Java 1.5. So check that your project's compiler compliance level is set to 1.5 or above (Project properties -> Java compiler).

Java 1.7 - generic error syntax

I get from github java project. I have java 1.7 version
there is code like this:
protected Set<Tag> tags = null;
private final Map<Tag, String> results;
protected AbstractAction() {
this.tags = new HashSet<>();
this.results = new HashMap<>();
}
I added it to eclipse, but there is error on new HashSet<>();
The error in eclipse is :
Multiple markers at this line
- Cannot instantiate the type HashSet
- Syntax error on token "<", ? expected after this token
- Type mismatch: cannot convert from HashSet to Set
- Syntax error on token "<", ? expected after this token
How do you think I can resolve it ?
Thank you.

The type inference feature was introduced in Java 7, and your code compiles correctly using the Java 7 JDK. Make sure you have configured the Java version level in the Eclipse project for Java 7 and not some earlier version.

Objectify generics compile time error with incompatible objects in Java 7

In java 6 the following line compiles however in Java 7 I get an incompatible type error (See below). Any ideas what is going on here?
Player player = new FPlayer();
player.setId("SomeString");
player.setWId(123456, "SomeString");
Key<Player> keyForPlayer = ofy().save().entity(player).now();
Gets a compile time error
incompatible types
required: com.googlecode.objectify.Key<com.XX.XXXXXX.XXXXX.XXXXXX.Player>
found: com.googlecode.objectify.Key<java.lang.Object>

JDK compiler error

Before anyone screams about EOL'ed JDK, I'd like to point out that my question is not about how to compile the following. There is a real question here and it's not about JDK 1.5 being EOL'ed...
The following under JDK 1.5, up to 1.5.0_22 (the last one I could find) produces on my system a compiler error:
private Object[] boozinga() {
boolean b = Math.abs(42) > 0;
Object[] res = new Object[1];
res[0] = b ? new int[1] : new String[1];
return res;
}
Changing the Math.abs(42) > 0 to true allows compilation.
Changing the ternary "assignment" to an if/else allows compilation.
Using JDK 1.6 allows compilation.
So I was wondering: is there something not legal in the above code under Java 1.5 and that is allowed under Java 1.6?
Does it crash for those of you that are under Java 1.5 too?
The crash says something like this:
An exception has occured in the
compiler (1.5.0_22). Please file a bug
at the Java Developer Connection
(http://java.sun.com/webapps/bugreport)
after checking the Bug Parade for
duplicates. Include your program and
the following diagnostic in your
report. Thank you.
I take it filling a bug report for an EOL'ed JDK is an exercice in futility but still, I'd still like to know if the above is valid Java 1.5 code or not.

I think it is legal. The evidence is that JDK 1.6.0_21 compiles it with options -source 1.5 -target 1.5. Can't you use JDK 1.6 with these options to compile and JRE 1.5 to run?
It crashes for me, too (JDK 1.5.0_12). It crashes for me even with:
public Object boozinga() {
boolean b = true;
Object res = b ? new int[1] : new String[1];
return res;
}
The difficulty for the compiler is that the type of b ? new int[1] : new String[1] is java.lang.Object & java.io.Serializable & java.lang.Cloneable.

The problem here is that the compiler has trouble to decide the type of the expression b ? new int[1] : new String[1]. I had something like this before (with 1.1.8 or 1.2, I think - but with a real error message, not a compiler crash), and then simply used a cast to help the compiler here.
res[0] = b ? (Object)new int[1] : new String[1];
I didn't look what the language specification says about this - but the compiler should never crash with an exception, it should give a real error message.